1995 GMC 1500 Turn signals

[bah614]

Just purchased a really great condition 1995 GMC 1500, only issue I have is over the drive home the turn signals stopped working. The hazards work fine, so I've concentrated my efforts on the flasher relay under the dash below the radio (the tricky one to find). First I swapped out to an electronic EP36 Led compatible one. The bulbs are all still incad, but it was the only one my autozone had. The clicking came back and it is clearly firing the relay but nothing lights up. So I picked up the non LED EP36 from Napa, it clicks once then does nothing.

My main question is when/how do I know if it is the multi function switch? That seems like the next likely culprit, but since it is a PITA I'd like to be certain it is. It makes sense because all was well until after a turn then it just stopped. The rest of the functions all work great, hazards, cruise, wipers, washer...

I'm pretty mechanically savvy, but electronics stump me a bit. I get that the power comes from the fuse to the multi-switch, then that energizes the flasher (I put a multimeter on it and see the 12v), but the flasher is only 1 output not separate for right and left, so I assume that then goes back to the switch to figure out where to send the "blink" right or left. I tried to test it by jumping a wire from across the relay (from the + to the output), I know it won't flash but it should come on solid, nothing did. So it seems the flasher is being triggered but the "output" isn't finding a path out.

I don't feel it is a ground/wire/bulb issue since the flashers work perfectly fine.

 

[TreeGeared]

You have it backwards. Power flows from the power distribution center to the multifunction switch to the lights. My guess is if you keep blowing a flasher you have a short in the multifunction switch or elsewhere in the system. I attached a wiring diagram. I suggest unplugging components and tracing to where you loose power.

 

[95burban]

BAH164 you wouldn’t happen to be a drag boat guy would ya?

 

[bah614]

Thanks TreeGeared, that makes sense and your diagram looks like the correct one, the HAYES book and other online ones are all incorrect in that they don't show the turn flasher, and hazard flasher separately (I think gm may have changed it in a later year model). I don't think there is a short past the switch since the hazards work fine and that all uses the same ground/wires/bulbs as the turn signals.

Since I've asked around and everyone says replace the multi, I guess I'll take the plunge as there isn't any more of a definitive test.

And no I'm not a drag boat guy. I've owned too many boats, RV's, and swimming pools in my life and learned the valuable lesson that you should never own them, just know someone else that has them

 

[CK99]

bah614....I see this post was nearly a year ago. I have exactly the same problem on the same model. I bought mine a couple of months ago. Turn signals worked during the pre-purchase inspection. I bought the truck, drove it around for a few days, then went to my daughter's house to pick up my boat. Hooked up the trailer, all was well, but when I un-hooked the boat, I no longer had turn signals nor back up lights. Fuse number 16 controls both of those and the fuse is good. However no power coming to the fuse plug. I checked the flasher (or relay) by hooking it up to a battery and it clicked. So....I replaced the multi function switch. (Next time I'm going to schedule a root canal with my dentist.....much less painful)! Got everything hooked up and no dice! Nothing has changed. Running ligths, brake lights and hazzard lights all work. No turn signals. Any ideas?